smp.c

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/*
 * Copyright (C) 2001, 2002, 2003 Broadcom Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/sched.h>

#include <asm/mmu_context.h>
#include <asm/io.h>
#include <asm/fw/cfe/cfe_api.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>

static void *mailbox_set_regs[] = {
    IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_SET_CPU),
    IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_SET_CPU)
};

static void *mailbox_clear_regs[] = {
    IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_CLR_CPU),
    IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_CLR_CPU)
};

static void *mailbox_regs[] = {
    IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_CPU),
    IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_CPU)
};

/*
 * SMP init and finish on secondary CPUs
 */
void __cpuinit sb1250_smp_init(void)
{
    unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
        STATUSF_IP1 | STATUSF_IP0;

    /* Set interrupt mask, but don't enable */
    change_c0_status(ST0_IM, imask);
}

/*
 * These are routines for dealing with the sb1250 smp capabilities
 * independent of board/firmware
 */

/*
 * Simple enough; everything is set up, so just poke the appropriate mailbox
 * register, and we should be set
 */
static void sb1250_send_ipi_single(int cpu, unsigned int action)
{
    __raw_writeq((((u64)action) << 48), mailbox_set_regs[cpu]);
}

static inline void sb1250_send_ipi_mask(const struct cpumask *mask,
                    unsigned int action)
{
    unsigned int i;

    for_each_cpu(i, mask)
        sb1250_send_ipi_single(i, action);
}

/*
 * Code to run on secondary just after probing the CPU
 */
static void __cpuinit sb1250_init_secondary(void)
{
    extern void sb1250_smp_init(void);

    sb1250_smp_init();
}

/*
 * Do any tidying up before marking online and running the idle
 * loop
 */
static void __cpuinit sb1250_smp_finish(void)
{
    extern void sb1250_clockevent_init(void);

    sb1250_clockevent_init();
    local_irq_enable();
}

/*
 * Final cleanup after all secondaries booted
 */
static void sb1250_cpus_done(void)
{
}

/*
 * Setup the PC, SP, and GP of a secondary processor and start it
 * running!
 */
static void __cpuinit sb1250_boot_secondary(int cpu, struct task_struct *idle)
{
    int retval;

    retval = cfe_cpu_start(cpu_logical_map(cpu), &smp_bootstrap,
                   __KSTK_TOS(idle),
                   (unsigned long)task_thread_info(idle), 0);
    if (retval != 0)
        printk("cfe_start_cpu(%i) returned %i\n" , cpu, retval);
}

/*
 * Use CFE to find out how many CPUs are available, setting up
 * cpu_possible_mask and the logical/physical mappings.
 * XXXKW will the boot CPU ever not be physical 0?
 *
 * Common setup before any secondaries are started
 */
static void __init sb1250_smp_setup(void)
{
    int i, num;

    init_cpu_possible(cpumask_of(0));
    __cpu_number_map[0] = 0;
    __cpu_logical_map[0] = 0;

    for (i = 1, num = 0; i < NR_CPUS; i++) {
        if (cfe_cpu_stop(i) == 0) {
            set_cpu_possible(i, true);
            __cpu_number_map[i] = ++num;
            __cpu_logical_map[num] = i;
        }
    }
    printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
}

static void __init sb1250_prepare_cpus(unsigned int max_cpus)
{
}

struct plat_smp_ops sb_smp_ops = {
    .send_ipi_single    = sb1250_send_ipi_single,
    .send_ipi_mask      = sb1250_send_ipi_mask,
    .init_secondary     = sb1250_init_secondary,
    .smp_finish     = sb1250_smp_finish,
    .cpus_done      = sb1250_cpus_done,
    .boot_secondary     = sb1250_boot_secondary,
    .smp_setup      = sb1250_smp_setup,
    .prepare_cpus       = sb1250_prepare_cpus,
};

void sb1250_mailbox_interrupt(void)
{
    int cpu = smp_processor_id();
    int irq = K_INT_MBOX_0;
    unsigned int action;

    kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
    /* Load the mailbox register to figure out what we're supposed to do */
    action = (____raw_readq(mailbox_regs[cpu]) >> 48) & 0xffff;

    /* Clear the mailbox to clear the interrupt */
    ____raw_writeq(((u64)action) << 48, mailbox_clear_regs[cpu]);

    if (action & SMP_RESCHEDULE_YOURSELF)
        scheduler_ipi();

    if (action & SMP_CALL_FUNCTION)
        smp_call_function_interrupt();
}